Light emitting device

ABSTRACT

Disclosed is a light emitting device. The light emitting device comprises: a first lead and a second lead which are spaced apart from each other; a body part comprising a base, a reflector, and a cavity; and a light emitting diode which is disposed in the cavity, wherein the first lead includes a first bottom lead and a first top lead located on the first bottom lead, and the second lead includes a second bottom lead and a second top lead located on the second bottom lead, and wherein a separation region between the first top lead and the second top lead has a different shape than the separation region between the first bottom lead and the second bottom lead, the separation region between the first top lead and the second top lead having a shape bent at least once.

CROSS REFERENCE TO RELATED APPLICATION

This application is a Continuation of U.S. patent application Ser. No.15/306,386, filed Oct. 24, 2016, which is the National Stage Entry ofInternational Application No. PCT/KR2015/003936, filed Apr. 20, 2015,and claims priority from Korean Patent Application No. 10-2014-0048174,filed Apr. 22, 2014, each of which is incorporated herein by referencefor all purposes as if fully set forth herein.

BACKGROUND Field

Exemplary embodiments of the present disclosure relate to a lightemitting device and, more particularly, to a light emitting device withimproved strength.

A light emitting diode refers to an inorganic semiconductor deviceconfigured to emit light through recombination of electrons and holesand has been used in various fields including displays, car lamps,general lighting, and the like. With many advantages of the lightemitting diode such as long lifespan, low power consumption and rapidresponse, a light emitting device such as a light emitting diode packageincluding such a light emitting diode is expected to replace typicallight sources.

A light emitting device including a light emitting diode may bemanufactured in various forms according to purposes thereof and thestructure of the light emitting device is determined by taking luminousefficacy and durability into account. FIG. 1A and FIG. 1B show oneexample of a typical light emitting device including a light emittingdiode.

Referring to FIG. 1A and FIG. 1B, a typical light emitting deviceincludes: a body 20 including a base 21, a reflector 23 and a cavity 25surrounded by the reflector 23; a first lead 11 and a second lead 13secured to the body 20 and partially exposed to the cavity 25 and alower surface of the body 20; and a light emitting diode 30 disposed onan upper surface of at least one of the leads 11, 13 and electricallyconnected to the leads 11, 13. In the light emitting device, the firstlead 11 and the second lead 13 are separated from each other and a space(region around line C-C′) between both leads 11, 13 is occupied by thebase 21.

Generally, the cavity 25 occupies a large area in the overall area ofthe base 21 in order to improve luminous efficacy of the light emittingdevice. That is, as shown in FIG. 1A, the lateral thickness of thereflector 23 is reduced to increase the area of the cavity 25, therebyimproving luminous efficacy of the light emitting device. Furthermore,in consideration of the structural characteristics of a wire and heatdissipation efficiency, the leads 11, 13 are generally formed to have alarge area.

When the light emitting device with the structure as described above issubjected to external impact or stress, the base 21 in the space (regionaround line C-C′) between the first lead 11 and the second lead 13 isdamaged. Particularly, when the base 21 in the region between the firstlead 11 and the second lead 13 is damaged, the wire 31 is likely to bedisconnected, thereby causing failure of the light emitting device.However, in consideration of luminous efficacy and heat dissipationefficiency is limited due to a decrease of the area of the cavity 25 oran increase in separation distance between the leads 11, 13. Therefore,there is a need for a light emitting device to have high reliabilitywhile maintaining the same level of luminous intensity as a typicallight emitting device in the art.

SUMMARY

Exemplary embodiments of the present disclosure provide a light emittingdevice that exhibits high strength with respect to external impact orstress.

Exemplary embodiments of the present disclosure provide a light emittingdevice that has high strength while maintaining the same level ofluminous intensity as a typical light emitting device in the art.

In accordance with one aspect of the present disclosure, a lightemitting device includes: a first lead and a second lead separated fromeach other; a body including a base at least partially surrounding sidesurfaces of the first and second leads and filling a separation regionbetween the first and second leads, a reflector disposed on the base,and a cavity surrounded by the reflector and open at an upper sidethereof; and a light emitting diode disposed in the cavity, wherein thefirst lead includes a first bottom lead and a first top lead disposed onthe first bottom lead, the second lead includes a second bottom lead anda second top lead disposed on the second bottom lead, a separationregion between the first top lead and the second top lead has adifferent shape than the separation region between the first bottom leadand the second bottom lead, and the separation region between the firsttop lead and the second top lead has a shape bent at least once.

In the light emitting device, the base disposed in the separation regionbetween the leads has improved strength, thereby improving reliabilityof the light emitting device.

In addition, the first top lead may include a first protrusion and afirst indentation formed on a side surface thereof facing the second toplead, and the second top lead may include a second protrusion and asecond indentation formed on a side surface thereof facing the first toplead.

Further, the first protrusion may be disposed in a region of the firsttop lead corresponding to the second indentation and the secondprotrusion may be disposed in a region of the second top leadcorresponding to the first indentation.

The first protrusion may be formed corresponding to the secondindentation to engage therewith and the second protrusion may be formedcorresponding to the first indentation to engage therewith.

In other exemplary embodiments, the first protrusion and the firstindentation may be placed at opposite ends of the side surface of thefirst top lead facing the second top lead, respectively, and the secondprotrusion and the second indentation may be placed at opposite ends ofthe side surface of the second top lead facing the first top lead,respectively.

A region of the side surface interposed between the first protrusion andthe first indentation may have a linear shape.

The separation region between the first protrusion and the secondindentation and the separation region between the second protrusion andthe first indentation may be placed under the reflector.

In some exemplary embodiments, the first bottom lead and the secondbottom lead may include a first chamfered portion and a second chamferedportion formed at corners of the side surfaces of the first bottom leadand the second bottom lead facing each other, respectively.

The first bottom lead or the second bottom lead may not be disposed in aregion under the first protrusion and in a region under the secondprotrusion.

In other exemplary embodiments, at least one of the first bottom leadand the second bottom lead may include a chamfered portion formed at acorner of each of the side surfaces of the first bottom lead and thesecond bottom lead facing each other.

A ratio (R/W2) of degree of chamfer R of the chamfered portion to widthW2 of one side surface of the light emitting device may be greater than0.052 to 0.25.

The first bottom lead and the second bottom lead may be disposed inregions of the first top lead and the second top lead, respectively.

A ratio (W1/W2) of width W1 of the cavity corresponding to across-section parallel to one side surface of the light emitting deviceto width W2 of the one side surface of the light emitting device may be0.8 to less than 0.92.

The light emitting device may further include a light emitting diodedisposed in the cavity.

In accordance with another aspect of the present disclosure, a leadincludes a first lead and a second lead separated from each other,wherein the first lead includes a first bottom lead and a first top leaddisposed on the first bottom lead, the second lead includes a secondbottom lead and a second top lead disposed on the second bottom lead, aseparation region between the first top lead and the second top lead hasa different shape than the separation region between the first bottomlead and the second bottom lead, and the separation region between thefirst top lead and the second top lead has a shape bent at least once.

The first top lead may include a first protrusion and a firstindentation formed on a side surface thereof facing the second top lead,and the second top lead may include a second protrusion and a secondindentation formed on a side surface thereof facing the first top lead.

The first protrusion may be disposed in a region of the first top leadcorresponding to the second indentation and the second protrusion may bedisposed in a region of the second top lead corresponding to the firstindentation.

The first protrusion may be formed corresponding to the secondindentation to engage therewith and the second protrusion may be formedcorresponding to the first indentation to engage therewith.

The first protrusion and the first indentation may be placed at oppositeends of the side surface of the first top lead facing the second toplead, respectively, and the second protrusion and the second indentationmay be placed at opposite ends of the side surface of the second toplead facing the first top lead, respectively.

A region of the side surface interposed between the first protrusion andthe first indentation may have a linear shape.

The first bottom lead and the second bottom lead may include a firstchamfered portion and a second chamfered portion formed at corners ofthe side surfaces of the first bottom lead and the second bottom leadfacing each other, respectively.

The first bottom lead or the second bottom lead may not be disposed in aregion under the first protrusion and in a region under the secondprotrusion.

At least one of the first bottom lead and the second bottom lead mayinclude a chamfered portion formed at a corner of each of the sidesurfaces of the first bottom lead and the second bottom lead facing eachother.

According to exemplary embodiments, the light emitting device includesprotrusions, indentations and/or chamfered portions formed on a sidesurface facing leads, whereby a region between the leads can haveimproved strength. As a result, the light emitting device according tothe exemplary embodiments has improved reliability.

In addition, the light emitting device includes a reflector, a lateralthickness of which is thickened without deterioration in luminousintensity, thereby providing improved strength while securing the samelevel of luminous intensity as a typical light emitting device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a top view of a typical light emitting device.

FIG. 1B is a side sectional view of a typical light emitting device.

FIG. 2 is a light emitting device according to an exemplary embodimentof the present disclosure.

FIG. 3 is a bottom view of the light emitting device of FIG. 2.

FIG. 4 is a side sectional view of the light emitting device of FIG. 1.

FIG. 5A is a bottom view of leads according to an exemplary embodimentof the present disclosure.

FIG. 5B is a bottom perspective view of the leads of FIG. 5A.

FIG. 6, FIG. 7 and FIG. 8 are plan views illustrating experimentalexamples for evaluating strength improvement of light emitting devicesaccording to exemplary embodiments of the present disclosure.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Hereinafter, exemplary embodiments of the present disclosure will bedescribed in detail with reference to the accompanying drawings. Thefollowing embodiments are provided by way of example so as to fullyconvey the spirit of the present disclosure to those skilled in the artto which the present disclosure pertains. Accordingly, the presentdisclosure is not limited to the embodiments disclosed herein and canalso be implemented in different forms. In the drawings, widths,lengths, thicknesses, and the like of elements can be exaggerated forclarity and descriptive purposes. When an element is referred to asbeing “disposed above” or “disposed on” another element, it can bedirectly “disposed above” or “disposed on” the other element, orintervening elements can be present. Throughout the specification, likereference numerals denote like elements having the same or similarfunctions.

EXEMPLARY EMBODIMENTS

FIG. 2, FIG. 3, and FIG. 4 are a top view, a bottom view, and a sidesectional view of a light emitting device according to an exemplaryembodiment of the present disclosure, respectively. In addition, FIG. 5Aand FIG. 5B are a bottom view and a bottom perspective view of leadsaccording to one exemplary embodiment of the present disclosure,respectively.

Referring to FIG. 2, FIG. 3, and FIG. 4, the light emitting deviceaccording to the exemplary embodiment includes a first lead 100, asecond lead 200, a body 300, and a light emitting diode 30. The lightemitting device may further include a wire 31 and a molding portion 40.

The first lead 100 and the second lead 200 may be separated from eachother and disposed at a lower portion of the light emitting device toform part of a lower region of the light emitting device. Particularly,a separation region 340 between the first lead 100 and the second lead200 may be filled with a base 310, and a lower surface of the base 310may be flush with lower surfaces of the first and second leads 100, 200to provide a flat lower surface of the light emitting device.

The first lead 100 may include a first top lead 110 and a first bottomlead 120, and the second lead 200 may include a second top lead 210 anda second bottom lead 220. The first top and bottom leads 110, 120 may beintegrally formed with each other, and the second top and bottom leads210, 220 may also be integrally formed with each other. The first lead100 and the second lead 200 may include a material exhibiting highelectric and thermal conductivity, for example, a metal or a metalalloy.

A portion of the separation region 340 that is positioned between thefirst top lead 110 and the second top lead 210 may have a differentshape than another portion of the separation region 340 that ispositioned between the first bottom lead 120 and the second bottom lead220. The separation region 340 that is positioned between the first toplead 110 and the second top lead 210 has a shape bent at least once.Referring to FIG. 2, the separation region 340 that is positionedbetween the first top lead 110 and the second top lead 210 bent at thebent region 350.

Next, referring to FIG. 2, FIG. 3, FIG. 4, FIG. 5A, and FIG. 5B, thefirst and second leads 100, 200 according to the exemplary embodimentwill be described in more detail.

First, the first lead 100 includes the first top lead 110 and the firstbottom lead 120. The first top lead 110 may be disposed on the firstbottom lead 120, have a larger area than the first bottom lead 120, andbe placed in a region occupied by the first top lead 110. Accordingly,only the first top lead 110 is exposed on an upper surface of the firstlead 100 in a top view of the first lead 100. Further, an edge 130 maybe formed on a side surface of the first lead 100 due to a difference inarea between the first top and bottom leads 110, 120, as shown in FIG.4. Such an edge 130 is filled with the base 310, whereby the first lead100 and the body 300 can be more firmly secured to each other.

The second lead 200 also includes the second top lead 210 and the secondbottom lead 220. The second top lead 210 may be disposed on the secondbottom lead 220, have a larger area than the second bottom lead 220, andbe placed in a region occupied by the second top lead 210. Accordingly,only the second top lead 210 is exposed on an upper surface of thesecond lead 200 in a top view of the second lead 200. Further, an edge230 may be formed on a side surface of the first lead 200 due to adifference in area between the second top and bottom leads 210, 220, asshown in FIG. 4. Such an edge 230 is filled with the base 310, wherebythe second lead 200 and the body 300 can be more firmly secured to eachother.

The first top lead 110 may include a first protrusion 111 formed on aside surface thereof facing the second top lead 210 to protrude towardthe second top lead 210 and a first indentation 113 formed thereon to bedepressed in an opposite direction to the second top lead 210. Thesecond top lead 210 may also include a second protrusion 211 and asecond indentation 213 formed on a side surface thereof facing the firsttop lead 110.

The second indentation 213 may be placed in a region of the second toplead 210 corresponding to the first protrusion 111 and the firstindentation 113 may be placed in a region of the first top lead 110corresponding to the second protrusion 211. Namely, as shown in FIG. 2,FIG. 5A, and FIG. 5B, the first protrusion 111 and the secondindentation 213 may be disposed in the corresponding regions so as toengage with each other, and the second protrusion 211 and the firstindentation 113 may also be disposed in the corresponding regions so asto engage with each other.

The first protrusion 111 and the first indentation 113 may be placed atopposite ends of the side surface of the first lead 100 facing thesecond lead 200. In addition, the second protrusion 211 and the secondindentation 213 may be placed at opposite ends of the side surface ofthe second lead 200 facing the first lead 100. In this structure, theside surface of the first lead 100 in a region between the firstprotrusion 111 and the first indentation 113 and the side surface of thesecond lead 200 in a region between the second protrusion 211 and thesecond indentation 213 may have a linear shape and be parallel to eachother. However, it should be understood that other implementations arealso possible and a separation region 340 between the first lead 100 andthe second lead 200 may have various shapes. That is, in other exemplaryembodiments, the separation region 340 between the first top lead 110and the second top lead 210 may have other shapes instead of the linearshape.

The light emitting device according to an exemplary embodiment includesthe leads each having the protrusion and the indentation formed thereonsuch that the protrusions engage with the corresponding indentations.Accordingly, even in the case where cracks are generated at a distal endof the separation region between the first lead 100 and the second lead200, propagation of the cracks can be blocked due to the presence of abent portion 350 in the separation region between the leads. That is,the protrusions and the indentations formed to engage with each otherand placed at the opposite ends of the side surfaces of the leads facingeach other can efficiently prevent generation and propagation of cracks.With this structure, the light emitting device has improved strength andcan secure good reliability. Particularly, since the indentations andthe protrusions are formed on the side surfaces of the leads facing eachother in order to improve strength of the light emitting device, thestrength of the light emitting device can be improved without increasingthe separation distance between the leads or modifying other componentsof the light emitting device.

Each of the first top lead 110 and the second top lead 120 may includefine protrusions 140 or 240 formed on other side surfaces thereofexcluding the sides surfaces thereof facing each other. A space betweenthe fine protrusions 140 or 240 may be filled with the base 310(described more below). With the structure wherein the fine protrusions140, 240 are further formed on the first top lead 110 and the second toplead 120, the light emitting device can effectively prevent the leads100, 200 from being detached or separated from the base 310.

The first bottom lead 120 and the second bottom lead 220 are disposedunder the first top lead 110 and the second top lead 210, respectively.

The first bottom lead 120 may include a first chamfered portion 121formed on the side surface thereof facing the second bottom lead 220.The second bottom lead 220 may also include a second chamfered portion221 formed on the side surface thereof facing the first bottom lead 120.

As shown in the drawings, each of the first chamfered portion 121 andthe second chamfered portion 221 may be formed at opposite ends of eachof the side surfaces of the first bottom lead 120 and the second bottomlead 220 facing each other. With this structure, a separation distancebetween the first bottom lead 120 and the second bottom lead 220 maygradually increase from a central region of each of the side surfacesthereof facing each other to a corner thereof.

Since the corners of the lower first and second leads 120, 220 arereplaced by the first chamfered portion 121 and the second chamferedportion 221, respectively, the lower first and second leads 120, 220 maynot be placed under the first protrusion 111 and the second protrusion211, respectively. Accordingly, a portion of the base 310 placed at theopposite ends of the separation region 340 between the leads 100, 120can have further improved strength.

The degree of chamfer of each of the first and second chamfered portions121, 221 may be adjusted in various ways and determined by taking intoaccount the strength of the light emitting device and heat dissipationefficiency provided by the leads. Herein, as shown in FIG. 3, a distancefrom a chamfering start point on each of the side surfaces facing eachother to a vertex point at a bent portion formed by chamfering isdefined as the degree of chamfer R. Here, the degree of chamfer R may beadjusted in various ways depending upon the size of the light emittingdevice. For example, when the width of one side surface of the lightemitting device parallel to a virtual line indicating the degree ofchamfer R is defined as W2, a ratio (R/W2) of the degree of chamfer R tothe width W2 may be greater than 0.052 to 0.25. For example, for a lightemitting device, one side surface of which has a width W2 of 5 mm, thedegree of chamfer R may be greater than 0.26 mm to 1.25 mm.

Such a degree of chamfer R may be applied to both the first bottom lead120 and the second bottom lead 220. In addition, the chamfered portionshaving the same degree of chamfer R or the different degrees of chamberR may be formed on all of corners of the side surfaces of the leadsfacing each other.

One mechanism of damage to the separation region 340 between the leadsis generation of cracks at the opposite ends of the separation region340 between the leads and propagation of the cracks along the separationregion 340 therebetween. However, according to the exemplary embodiment,the chamfered portions are formed on the side surfaces of the lowerleads facing each other, thereby effectively preventing generation ofcracks in the base 310 at the opposite ends of the separation region 340between the leads. With this structure, the light emitting device canhave improved strength.

Referring to FIG. 2, FIG. 3, FIG. 4, FIG. 5A, and FIG. 5B again, atleast one of the first lead 100 and the second lead 200 may include atleast one through-hole 115, 215 vertically formed therethrough. Thethrough-holes 115, 215 may be filled with the base 310, whereby the base310 can be more firmly secured to the leads 100, 200.

The through-holes 115, 215 may have an inclined side surface and an endportion. With this structure, an upper opening of each of thethrough-holes 115, 215 may have a different area than a lower openingthereof.

Referring to FIG. 2, FIG. 3, and FIG. 4 again, the body 300 may includethe base 310, a reflector 320, and a cavity 330.

The base 310 surrounds at least part of the side surfaces of the firstand second leads 100, 200, and particularly, fills the separation region340 between the first lead 100 and the second lead 200. Upper and lowersurfaces of the first lead 100 and the second lead 200 may be exposed,whereby an upper surface of the base 310 may be generally coplanar andflush with the upper surfaces of the leads 100, 200 and a lower surfaceof the base 310 may be generally coplanar and flush with the lowersurfaces of the leads 100, 200. However, it should be understood thatother implementations are also possible. On the other hand, the fineprotrusions 140, 240 may be exposed through side surfaces of the base310. The base 310 can act as a substrate of the light emitting devicetogether with the leads 100, 200.

The base 310 may include a ceramic or polymer material, for example, asilicone, polyamide, or epoxy resin. Furthermore, the base 310 mayfurther include fillers such as TiO₂.

The reflector 320 may be disposed along an outer periphery of a lowerregion of the light emitting device, which is composed of the base 310and the leads 100, 200, whereby the cavity 300 may be formed in a regionsurrounded by the reflector 320. The first and second leads 100, 200 andthe base 310 may be partially exposed to a lower surface of the cavity300.

The reflector 320 may serve to reflect light emitted from the lightemitting diode 30 towards an upper portion of the light emitting deviceand may have an inclined inner side surface in order to secure moreefficient reflection.

A lateral thickness of the reflector 320 may be determined inconsideration of strength and luminous intensity of the light emittingdevice, as needed. With a structure wherein the reflector 320 has alarge lateral thickness, luminous intensity of the light emitting devicecan be deteriorated due to a decrease in the area of the cavity 300 froman increase in the thickness of the reflector, despite improved strengthof the light emitting device.

In order to maintaining luminous intensity of the light emitting devicewhile improving strength of the light emitting device, the lateralthickness of the reflector 320 may be determined as follows. Referringto FIG. 4, in a cross-section taken along a virtual line penetrating thecenter of the light emitting device and parallel to one side surfacethereof, the overall width of the cross-section is defined as W2 and thewidth of an upper portion of the cavity 330 is defined as W1. Here,W1/W2 may be 0.8 to less than 0.92. For example, in a light emittingdevice having a width W2 of 5 mm, the cavity 330 may have a width W1 of4.0 mm to less than 4.6 mm. With this structure, the light emittingdevice can have improved strength while maintaining luminous intensity,thereby improving reliability.

The reflector 320 can cover the protrusions 111, 211 and the indentation113, 213 of the first and second leads 100, 200. Accordingly, a portionhaving a linear shape in the separation region 340 between the first toplead 110 and the second top lead 210 can be exposed to the lower surfaceof the cavity 330. This structure can more effectively preventgeneration of cracks at the opposite ends of the separation region 340between the first lead 100 and the second lead 200. However, it shouldbe understood that other implementations are possible.

The reflector 320 may include a ceramic or polymer material, forexample, a silicone, polyamide, or epoxy resin. Furthermore, thereflector 320 may further include fillers such as TiO₂.

The reflector 320 and the base 310 may be integrally formed with eachother. Alternatively, the reflector 320 and the base 310 may be formedas separate components. When the reflector 320 and the base 310 areintegrally formed with each other, the reflector 320 and the base 310may be formed at the same time through molding once.

The light emitting diode 30 may be placed on at least one of the firstlead 100 and the second lead 200. The light emitting diode 30 may beselected from various light emitting diodes known to those skilled inthe art. The light emitting diode 30 may be a lateral, vertical, orflip-chip type light emitting diode and electrical connection of thelight emitting diode may be determined depending upon the shape thereof.For example, as shown in the drawings, the light emitting diode 30 maybe a vertical type light emitting diode and may be disposed on thesecond lead 200 to be electrically connected to the second lead 200through the lower surface thereof and to be electrically connected tothe first lead 100 through the wire 31.

Furthermore, although the light emitting device is illustrated asincluding one light emitting diode 30 in this exemplary embodiment, itshould be understood that other implementations are possible and thelight emitting device may include a plurality of light emitting diodes30.

Description of details of the light emitting diode 30 known in the artwill be omitted.

The light emitting device may further include the molding portion 40,which fills the cavity 300 and encapsulates the light emitting diode 30.The molding portion 40 may have light transmittance and may include, forexample, a silicone or polymer material.

EXPERIMENTAL EXAMPLES

FIG. 6, FIG. 7, and FIG. 8 are plan views illustrating experimentalexamples for evaluating strength improvement of light emitting devicesaccording to exemplary embodiments of the present disclosure. Theseexperimental examples are provided for illustration of improvement instrength and deterioration in luminous intensity of light emittingdevices according to exemplary embodiments of the present disclosure.The light emitting devices used in the experimental examples had a sizeof 5×5 mm². In addition, the light emitting diode of each of the lightemitting devices was manufactured by Seoul Viosys Co., Ltd. and had asize of 650×1300 μm².

First Experimental Example

In a first experimental example, influence of the lateral thickness ofthe reflector on luminous intensity of the light emitting device wasevaluated. Referring to FIG. 6, Samples 1, 2, and 3 had a W2 of 5 mm anda W1 of 4.6 mm, 4.2 mm, or 4.0 mm. Table 1 shows luminous intensity ofthe light emitting diode, luminous flux of the light emitting device,and a k-factor indicating a ratio of luminous intensity of the lightemitting diode to luminous flux of the light emitting device. Thek-factor can be calculated as follows.

${k - {factor}} = \frac{{Luminous}\mspace{14mu} {flux}\mspace{14mu} {of}\mspace{14mu} {light}\mspace{14mu} {emitting}\mspace{14mu} {device}}{( {{Luminous}\mspace{14mu} {intensity}\mspace{14mu} {of}\mspace{14mu} {light}\mspace{14mu} {emitting}\mspace{14mu} {diode}} ) \times 1000}$

TABLE 1 Luminous flux of light Luminous intensity of light emittingdevice emitting diode (lm) (mW) k-factor Sample 1 164.67 0.459 0.358 (W1= 4.6 mm) Sample 2 165.65 0.464 0.357 (W1 = 4.2 mm) Sample 3 164.480.460 0.357 (W1 = 4.0 mm)

According to this experimental example, it can be seen that, even in thecase where the width of the cavity was decreased from 4.6 mm to 4.0 mmby increasing the lateral thickness of the reflector, the k-factor wasremained at substantially the same level. That is, it can be seen that,even in the case where the width of the cavity was decreased to 0.8times that of one side surface of the light emitting device in order toincrease strength of the light emitting device, luminous intensity ofthe light emitting device was generally maintained.

Second Experimental Example

In a second experimental example, strength of the light emitting devicedepending upon the presence of protrusions and indentations on the firstlead and the second lead was measured. Strength of the light emittingdevice was measured using a push-pull gauge system. As shown in FIG. 7,load was applied to points A and B. Table 2 shows measurement results ofstrength depending upon the width of the cavity and the presence of theprotrusions and the indentations.

TABLE 2 W1 = 4.6 W1 = 4.2 W1 = 4.0 Point A Point B Point A Point B PointA Point B Absence of 0.977 0.584 1.369 0.848 1.742 1.038 protrusion andindentation (kg) Presence of 1.043 0.616 1.465 0.898 1.868 1.100protrusion and indentation (kg) Strength 106.8% 105.5% 107.0% 105.9%107.2% 106.0% increase ratio (%)

According to the second experimental example, it can be seen that theprotrusions and indentations on the leads increased strength both in acentral portion and an outer peripheral portion of the separation regionbetween the leads. Further, it can be seen that the light emittingdevice including both the reflector with an increased lateral thicknessand the structure of the protrusions and the indentations had thehighest strength increase ratio.

Third Experimental Example

In a third experimental example, strength of the light emitting devicedepending upon the degree of chamfer of the chamfered portions of thefirst lead and the second lead was measured. Strength of the lightemitting device was measured using a push-pull gauge system. As shown inFIG. 8, load was applied to points A and B. Tables 3 and 4 showmeasurement results of strength depending upon the width of the cavityand the degree of chamfer of the chamfered portions.

TABLE 3 W1 = 4.6 W1 = 4.2 W1 = 4.0 Strength Strength Strength increaseincrease increase ratio ratio ratio Point A (%) Point A (%) Point A (%)R = 0.26 mm 0.744   100% 1.088   100% 1.252   100% R = 0.66 mm 0.977131.3% 1.369 125.8% 1.742 139.1% R = 1.06 mm 1.051 141.3% 1.558 143.2%1.823 145.6%

TABLE 4 W1 = 4.6 W1 = 4.2 W1 = 4.0 Strength Strength Strength increaseincrease increase ratio ratio ratio Point B (%) Point B (%) Point B (%)R = 0.26 mm 0.388 100.0% 0.600 100.0% 0.780 100.0% R = 0.66 mm 0.546140.7% 0.765 127.5% 0.878 112.6% R = 1.06 mm 0.584 150.5% 0.848 141.3%1.038 133.1%

According to the third experimental example, it can be seen that, in thestructure wherein the leads include the chamfered portions, strength wasincreased both in a central portion and an outer peripheral portion ofthe separation region between the leads.

It should be understood that the present disclosure is not limited tothe above exemplary embodiments and experimental examples, and that thatvarious modifications and changes can be made to the present inventionwithout departing from the spirit and scope of the present disclosure,as defined by the appended claims and equivalents thereof.

What is claimed is:
 1. A light emitting device, comprising: a first leadand a second lead being separated from each other by a separation space,the first lead comprising a first top lead and a first bottom lead andthe second lead comprising a second top lead and a second bottom lead; abase surrounding at least part of the side surfaces of the first andsecond leads, the base filling the separation space between the firstlead and the second lead; a reflector disposed along an outer peripheryof a lower region of the light emitting device; a cavity being formed ina region surrounded by the reflector, the first and second leads and thebase being partially exposed to a lower surface of the cavity; and alight emitting diode being placed on at least one of the first andsecond leads, wherein the first top lead have a larger area than thefirst bottom lead, and the second top lead have a larger area than thesecond bottom lead, wherein the first top lead comprises a protrusionformed on a side surface thereof facing the second top lead, and thesecond top lead comprises an indentation which is placed in a region ofthe second top lead corresponding to the first protrusion.
 2. The lightemitting device according to claim 1, the first top and bottom leads areintegrally formed with each other.
 3. The light emitting deviceaccording to claim 1, the second top and bottom leads are integrallyformed with each other.
 4. The light emitting device according to claim1, a separation region between the first top lead and the second toplead has a different shape than a separation region between the firstbottom lead and second bottom lead.
 5. The light emitting deviceaccording to claim 1, the light emitting device further comprise a bentportion in the separation region between the leads.
 6. The lightemitting device according to claim 1, the first lead and the second leadcomprise at least one fine protrusion formed on other side surfacesthereof excluding the sides surfaces thereof each other.
 7. The lightemitting device according to claim 6, a space between the fineprotrusions is filled with the base.
 8. The light emitting deviceaccording to claim 6, the fine protrusions are formed at the top lead offirst and second lead.
 9. The light emitting device according to claim6, the fine protrusions are exposed through side surface of the base.10. The light emitting device according to claim 1, an upper and lowersurfaces of the first lead and the second lead is exposed.
 11. The lightemitting device according to claim 10, an upper surface of the base iscoplanar and flush with the upper surface of the leads.
 12. The lightemitting device according to claim 10, an lower surface of the base iscoplanar and flush with the lower surface of the leads.
 13. The lightemitting device according to claim 1, a ratio of overall width of thecross-section to a width of an upper portion of the cavity is 0.8 toless than 0.92.
 14. The light emitting device according to claim 1, thereflector and the base are integrally formed.
 15. The light emittingdevice according to claim 1, the light emitting diode is placed on atleast one of the first lead and second lead.
 16. The light emittingdevice according to claim 1, the light emitting diode is selected from alateral, vertical, or flip-chip type light emitting diode.